Join Date: Aug 2010
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I also use McMaster for many things. However all the bolts in the appropriate length are threaded all the way up to the head. I wanted a smooth 1/2 inch OD on the bolt to go into a smooth 1/2 inch ID on the chainplate. Since I was trying to avoid the point loading of the square carriage bolts I also didn't want the whole load bearing on just two or three threads.
In any chain plate installation the bolt should never carry any shearing load. The bolt is used to force the plate against the knee. The pressure creates so much friction that the plate does not move and puts no shear force on the bolt. If the chain plate is allowed to move then only one bolt will be carrying the entire shear load. That's bad for then one bolt will likely shear. Then another and another until they all fail.
Carriage bolts are often used because it's hard to put a wrench on both sides in some situations. The square shoulder is held from turning by the chain plate itself. They should not create point loading.
1995 Valiant 42